Accepted 28th July, 2015
Cnestis ferruginea leaves extract was studied as corrosion inhibitor for mild steel in 1MHCl at temperatures 300C and 450C using gravimetric and gasometric techniques. C. ferruginea leaves extract was found to inhibit corrosion of mild steel in acid medium. The inhibition efficiency increased as concentration of C. ferruginea extract increased but decreased with rise in temperature suggesting physical adsorption of the extract on mild steel surface. The calculated values of apparent activation energy, free energy of adsorption and heat of adsorption confirmed the physisorption mechanism. The inhibitor adsorption characteristics were approximated by the Langmuir isotherm.
Keywords: Cnestis ferruginea, eco-friendly inhibitor, gasometric techniques, mild steel